A retrofit blend for R-12 refrigeration systems, similar to R-401A. The pressure and system capacity match R-12 when the blend is running at lower evaporator temperatures (-20°F to -30°F). R-401B is also a good match to R-500 in air conditiong applications. There is about 8°F of temperature glide in the evaporator and condenser. Discharge pressure increases compared to R-12. The R-152a component, an HFC, hurts the miscibility with mineral oil. It is recommended to change some of the oil to alkylbenzene unless the system is small and running at higher evaporator temperatures.